Magnetic storage medium comprised of magnetic nanoparticles contained within nanotubes

ABSTRACT

A magnetic storage medium is formed of magnetic nanoparticles that are encapsulated within nanotubes (e.g., carbon nanotubes).

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/569,353, filed on Sep. 29, 2009, which is a continuation-in-part ofU.S. patent application Ser. No. 12/403,729, filed Mar. 13, 2009, bothof which are hereby incorporated by reference in their entirety. U.S.patent application Ser. No. 12/569,353 also claims the benefit of U.S.Provisional Patent Application No. 61/243,347, filed on Sep. 17, 2009,and is also hereby incorporated by reference in its entirety.

BACKGROUND

The pursuit of higher performance computing systems is driving thereduction in scale of magnetic storage media. Higher storage densitiesallow for the reduction of device sizes, an enhancement of devicecapabilities, and a reduction in data storage costs. To facilitate thisincrease in magnetic data storage density, industry is constantlysearching for structures and processes to reduce the size of informationstorage sectors and tracks on magnetic tape and magnetic disks.

Current magnetic media technology is based upon the ability to magnetizecells of magnetic materials that are deposited directly on a substratematerial. These substrate materials are flexible, in the case ofmagnetic tape of floppy disks, or rigid, in the case of hard disks. Thelaws of physics place an eventual limit on the ability to increase thestorage density of media that is formed of magnetic particles depositeddirectly on such a storage tape or disk. In the near future, themagnetic storage media industry will reach this storage density limit.It is therefore essential to find new technologies to replace directdeposition of magnetic materials to facilitate further increases inmagnetic storage media density.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

The present disclosure includes a method of writing information to amagnetic storage media that includes positioning a magnetic fieldgenerator over the magnetic storage media. The magnetic field generatorcan be formed of a carbon nanotube containing a magnetic nanoparticle.The magnetic storage media is formed of a plurality of carbon nanotubesthat each contains a plurality of magnetic nanoparticles. The methodincludes generating a magnetic field with the magnetic field generatorand imparting a polarization to at least one of the magneticnanoparticles in the magnetic media with the magnetic field. Thepolarization represents information.

The present disclosure also includes a method of writing information toa magnetic storage media that includes positioning a magnetic fieldgenerator, which is a Helmholtz coil, over the magnetic storage media.The Helmholtz coil includes a nano-wire wrapped around a carbonnanotube. The magnetic storage media includes a plurality of carbonnanotubes each containing a magnetic nanoparticle. The method includesgenerating a magnetic field with the magnetic field generator andimparting a polarization to the magnetic nanoparticles in the magneticmedia with the magnetic field where the polarization representsinformation.

The present disclosure also includes a method of writing information toa magnetic storage media that includes reading servo control informationfrom a servo sector located on the magnetic storage media. The servocontrol information is stored on the magnetic polarization of aplurality of magnetic nanoparticles within the servo sector. The methodincludes positioning a write-head over the magnetic storage media basedon the servo control information and writing information to the magneticstorage media with a magnetic field generator.

The present disclosure also includes a method of reading informationfrom magnetic storage media that includes positioning a read-head overthe magnetic storage media. The magnetic storage media includes aplurality of carbon nanotubes that each contains a magneticnanoparticle. The read-head includes a magnetic force microscopy probe.The method of reading includes detecting a polarization of a magneticnanoparticle contained within the magnetic storage media. Thepolarization represents data. The magnetic force microscopy probe thencommunicates the polarization to a controller.

The present disclosure also includes a method of reading informationfrom magnetic storage media that includes positioning a read-head over amagnetic storage media. The magnetic storage media includes a pluralityof carbon nanotubes that each contains a magnetic nanoparticle. Theread-head includes a cantilevered nanostructure having a probe end. Themethod includes deflecting the probe end with a polarization of themagnetic nanoparticle contained within the magnetic storage media. Thisdeflection generates a piezoelectric response in the cantileverednanostructure. It is then possible to determine the polarization of amagnetic nanoparticle contained within the magnetic storage media bymeasuring the piezoelectric response of the cantilevered nanostructure.

The present disclosure also includes a magnetic storage media thatincludes a plurality of data sectors. Each of these data sectorsincludes first carbon nanotubes that each contains a first magneticnanoparticle. The magnetic storage media also includes a plurality ofservo sectors. Each of these servo sectors includes second carbonnanotubes that each contains a second magnetic nanoparticle. The firstand second magnetic nanoparticles have a different coercivity.

The present disclosure also includes a magnetic storage media configuredto store information with a plurality of carbon nanotubes that eachcontains a magnetic nanoparticle. The information is represented by apolarization of each of the magnetic nanoparticles. Each of the magneticnanoparticles is held in a static position within each of the carbonnanotubes by friction.

The present disclosure also includes a write-head for magnetic storagemedia. The write-head includes a carbon nanotube containing a magneticnanoparticle and a nano-wire coiled around the carbon nanotube. Anelectrical current within the nano-wire generates a magnetic fieldwithin the carbon nanotube containing the magnetic nanoparticle.

The present disclosure also includes a write-head for magnetic storagemedia that includes a Helmholtz coil. The Helmholtz coil includes firstand second carbon nanotubes. Each of the nanotubes is wrapped with anano-wire. Passing an electric current through each nano-wire generatesa magnetic field through said Helmholtz coil.

The present disclosure also includes a read-head for magnetic storagemedia that includes a magnetic force microscopy probe configured todetect the polarization of a magnetic nanoparticle contained within acarbon nanotube that is encapsulated within a data layer.

The present disclosure also includes a read-head for magnetic storagemedia that includes a cantilevered carbon nanotube structure having aprobe tip. A magnetic nanoparticle contained within the probe tip isconfigured to interact with the magnetization of magnetic nanoparticlescontained within carbon nanotubes encapsulated within a magnetic storagemedia. The probe tip is deflected in response to the polarization of themagnetic storage media causing a change in the conductivity of thecantilevered carbon nanotube structure from which information stored onthe magnetic storage media can be read.

The present disclosure also includes a magnetic storage media thatincludes a carbon nanotube and a first magnetic nanoparticle configuredto store binary information through polarization. The first magneticnanoparticle is contained within the carbon nanotube. The media alsoincludes a second magnetic nanoparticle configured to store binaryinformation through polarization. The second magnetic nanoparticle isalso contained within the carbon nanotube. The media further includes anon-magnetic nanoparticle that is contained within the carbon nanotubebetween the first and second magnetic nanoparticles.

The present disclosure also includes a method of writing servo controlinformation to magnetic storage media. The method includes positioningmagnetic storage media within a bulk magnetic field. The magneticstorage media includes a plurality of carbon nanotubes each containing amagnetic nanoparticle. The carbon nanotubes are encapsulated within amatrix. The method further includes permanently magnetically polarizingfirst magnetic nanoparticles with the bulk magnetic field. The firstmagnetic nanoparticles are contained within carbon nanotubes locatedwithin a servo sector. The magnetic polarization represents servocontrol information.

The present disclosure also includes a method for manufacturing magneticstorage media that includes heating a magnetic nanoparticle above itsrespective Curie temperature to demagnetize the magnetic nanoparticle,cooling the magnetic nanoparticle and inserting the magneticnanoparticle into a carbon nanotube.

The present disclosure also includes a rotational marker on a magneticstorage disk. The magnetic storage disk has a center and an outer edge.The rotational marker includes a plurality of carbon nanotubes and aplurality of magnetic nanoparticles located within each of the carbonnanotubes. Each of the carbon nanotubes extend horizontally within aplane of the magnetic storage disk between the center and the outer edgeof the magnetic storage disk.

The present disclosure also includes grey code that includes a carbonnanotube containing magnetic nanoparticles magnetically polarized in auniform direction to signify a first digital state, and a non-magneticnanostructure having no magnetic polarization to signify a seconddigital state.

The present disclosure also includes a servo sector that includes greycode and fine positioning information. The grey code includes a carbonnanotube containing magnetic nanoparticles magnetically polarized in auniform direction to signify a first digital state, and a non-magneticnanostructure having no magnetic polarization to signify a seconddigital state. The fine positioning information is configured toindicate where a read/write head should be optimally positioned over adata track. The fine positioning information includes a patterned arrayof magnetic nanoparticles that are magnetically polarized.

The present disclosure also includes a data sector that includes a dataheader marker formed of a first carbon nanotube containing permanentlymagnetized magnetic nanoparticles interlaced with non-magneticnanoparticles. The data sector further includes a data header identifiercomprised of rewritable magnetic nanoparticles positioned adjacent tothe permanently magnetized nanoparticles within the first carbonnanotube. The data sector also includes a data block comprised ofrewritable magnetic nanoparticles positioned adjacent to the data headerwithin the first carbon nanotube. In addition, the data sector includeserror correction code positioned adjacent to said data block within saidfirst carbon nanotube. The error correction code may include magneticnanoparticles.

The present disclosure also includes a positioning nanostructure forfine-positioning a read/write head over a data track on magnetic media.The positioning nanostructure includes an array of parallel carbonnanotubes positioned perpendicular or at a gently curving arc relativeto a direction of movement of the magnetic media. The array of parallelcarbon nanotubes includes a patterned array of magnetic nanoparticles.The patterned array of magnetic nanoparticles informs a controller as towhether the read/write head is optimally positioned over a data track,or if it is positioned too high or too low.

The present disclosure also includes a method for positioning aread/write head over a data track of a magnetic storage medium. Themethod includes passing a read/write head over a first carbon nanotubecontaining first magnetically polarized magnetic nanoparticles andnon-magnetic nanoparticles. The method further includes detectingwhether there are any first magnetically polarized magneticnanoparticles under the read/write head. The method also includespassing a read/write head over a second carbon nanotube containingsecond magnetically polarized magnetic nanoparticles and non-magneticnanoparticles. The method still further includes detecting whether thereare any second magnetically polarized magnetic nanoparticles under theread/write head. In addition, the method includes directing theread/write head to remain in position over a data track with acontroller if the read/write head detected both the first and secondmagnetically polarized magnetic nanoparticles. Also, the method includesdirecting the read/write head to change position over the data trackwith a controller if the read/write head does not detect both the firstand second magnetically polarized magnetic nanoparticles.

The use of magnetic nanoparticles to store information facilitates avast increase in the storage density capability of magnetic storagemedia. Encapsulation of these magnetic nanoparticles within carbonnanotubes allows for the organization of the magnetic nanoparticles intotracks and sectors of information storage media that a read/write headof a storage device can store information.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 depicts an isometric view of magnetic nanoparticles encapsulatedwithin carbon nanotubes;

FIG. 2 depicts an isometric view of shunt nanoparticles encapsulatedwithin a shunt carbon nanotubes;

FIG. 3 depicts a cross section of a nano-scale magnetic medium havingmagnetic and shunt nanoparticles encapsulated within respective carbonnanotubes that are on a substrate;

FIG. 4 depicts a view of an arrangement of carbon nanotube data storagetracks on a magnetic tape;

FIG. 5 depicts a view of an arrangement of carbon nanotube data storagetracks on a disk;

FIG. 6 illustrates the magnetically enhanced cure of magnetic tape toassist in the orientation of carbon nanotubes that encapsulate magneticnanoparticles;

FIG. 7 illustrates the magnetically enhanced cure of a magnetic disk toassist in the orientation of carbon nanotubes that encapsulate magneticnanoparticles;

FIG. 8 illustrates a magnetic tape having carbon nanotubes in variousorientations within a data track;

FIG. 9 illustrates a magnetic disk having carbon nanotubes in variousorientations within an annular data track;

FIG. 10 illustrates a magnetic disk having carbon nanotubes in variousorientations within a spiral data track;

FIG. 11 illustrates a flow chart for manufacturing a magnetic diskhaving carbon nanotubes;

FIG. 12 illustrates a cross-sectional flow diagram for manufacturing amagnetic disk having carbon nanotubes;

FIG. 13 illustrates a flow chart for manufacturing a data recordinglayer;

FIG. 14 illustrates formation of a data recording layer;

FIG. 15 illustrates a flow chart for manufacturing a magnetic diskhaving carbon nanotubes;

FIG. 16 illustrates a cross-sectional flow diagram for manufacturing amagnetic disk having carbon nanotubes;

FIG. 17 illustrates a flow chart for manufacturing a magnetic tape or aflexible magnetic disk having carbon nanotubes;

FIG. 18 illustrates a cross-sectional flow diagram for manufacturing amagnetic tape or a flexible magnetic disk having carbon nanotubes;

FIGS. 19A, 19B and 19C illustrate a Hard Disk Drive (HDD) including ahard disk, a read/write head mounted to a servo-controlled arm and acontroller;

FIG. 20 illustrates a perspective view of a read/write head having acantilevered nanostructure read-head and a carbon nanotube write-read;

FIG. 21 illustrates a perspective view of a read-head having acantilevered nanostructure;

FIG. 22 illustrates a side view of a read/write head having acantilevered nano structure read-head and a carbon nanotube write-read;

FIG. 23 illustrates a magnetic field generator formed of a shaped carbonnanotube that contains a plurality of magnetic nanoparticles;

FIG. 24 illustrates a cantilevered nanostructure forming a component ofa read-head;

FIG. 25 illustrates a side view of a read/write head having a magneticforce microscopy probe read-head;

FIG. 26 illustrates a perspective view of a read/write head having amagnetic force microscopy probe read-head;

FIG. 27 illustrates a portion of a Helmholtz coil that includes anano-wire wrapped around a bobbin formed of a carbon nanotubes;

FIG. 28 illustrates a perspective view of a read/write head showing aportion of a write/head formed of a Helmholtz coil;

FIG. 29 illustrates a side view of a read/write head formed of aHelmholtz coil and accompanying magnetic storage media;

FIG. 30 illustrates a magnetic nanoparticle frictionally fit within acarbon nanotubes;

FIG. 31 illustrates a carbon nanotube containing magnetic nanoparticlesand non-magnetic nanoparticles;

FIG. 32 depicts exemplary array of nanotube assemblies forming arotational marker, a servo sector, a data header and a data block, asshown in FIGS. 19A and 19C;

FIG. 33 depicts a process flow diagram illustrating a method forfabricating magnetic media having magnetic nanoparticles containedwithin carbon nanotubes encapsulated within a matrix;

FIG. 34 illustrates a process flow diagram depicting a method of writinginformation to magnetic storage media that includes a carbon nanotubecontaining magnetic nanoparticles;

FIG. 35 illustrates a process flow diagram depicting a method of readinginformation from a magnetic storage media that includes a carbonnanotube containing magnetic nanoparticles;

FIG. 36 illustrates a process flow diagram depicting a method of writingservo control information to magnetic storage media; and

FIG. 37 illustrates a process flow diagram depicting a method for finepositioning of a read/write head over a data track.

DETAILED DESCRIPTION

FIG. 1 shows magnetic carbon nanotube assembly 100 comprising carbonnanotube 101. Carbon nanotube 101 is illustrated as a single-wall hollowtube formed of a single layer of carbon atoms in either hexagonallattice pattern 102 or 112 (FIG. 2). Since carbon nanotube 101 ishollow, it can contain nanoparticles 103 and 104. Carbon nanoparticle103 has a high magnetic coercivity so that it can permanently retain afirst magnetic field until that field is changed to a second magneticfield. Also, nanoparticle 103 is a particle which preferably does notoxidize or rust on ambient air, such as CrO₂ (chromium dioxide). Suchoxidation would cause the loss of the stored magnetic field.Nanoparticle 104 also has a high magnetic coercivity, so that it canpermanently retain a first magnetic field until that field is changed toa second magnetic field. Nanoparticle 104 contains high coercivity core105 which holds the permanent magnetic field. To prevent oxidation, core105 is encapsulated in shell 106. An example of core 105 is pure Fe(iron) and shell 106 is iron oxide, such as Fe₂O₃, which can be formedfor example by chemical vapor deposition (CVD) or atomic layerdeposition (ALD). Another example of shell 106 is aluminum oxide, Al₂O₃,commonly referred to as alumina, which can be formed for example bychemical vapor deposition (CVD). Another example of shell 106 is adiamond-like film coating. Amorphous (a-C) and hydrogenated amorphouscarbon (a-C:H) diamond-like films have high hardness, low friction,electrical insulation, chemical inertness, optical transparency,biological compatibility, ability to absorb photons selectively,smoothness, and resistance to wear. Several methods have been developedfor producing diamond-like carbon films: primary ion beam deposition ofcarbon ions (IBD); sputter deposition of carbon with or withoutbombardment by an intense flux of ions (physical vapor deposition orPVD); and deposition from an RF plasma, sustained in hydrocarbon gases,onto substrates negatively biased (plasma assisted chemical vapourdeposition or PACVD). Silicon and Silicon Oxide, Si and SiO₂, or anyoxide, may also be used for shell 106, which can be formed for exampleby chemical vapor deposition (CVD). Carbon nanotube 101 may contain asingle nanoparticle 103 or 104. Alternatively, carbon nanotube 101 maycontain multiple nanoparticles 103 or 104 and in any combinationthereof.

FIG. 2 shows shunt carbon nanotube assembly 110 comprising carbonnanotube 111. Like carbon nanotube 101, carbon nanotube 111 isillustrated as a single-wall hollow tube preferably formed of a singlelayer of carbon atoms in either hexagonal lattice pattern 112 or 102(FIG. 1). Hexagonal lattice 112 is rotated ninety degrees from hexagonallattice 102 and suitable nanotubes comprising either lattice can beused. Since carbon nanotube 111 is hollow, it can contain nanoparticles113 and 114. Carbon nanoparticle 113 has a low or zero magneticcoercivity so that it does not permanently retain a first magneticfield, which allows nanoparticle 113 to act as a magnetic shunt. Also,nanoparticle 113 is a particle which does not oxide or rust in ambientair, such as a soft-ferrite. Nanoparticle 114 also has low or zerocoercivity, so that it does not permanently retain a first magneticfield. Nanoparticle 114 contains low or zero coercivity core 115 whichprovides the desired magnetic shunt. To prevent oxidation, core 115 isencapsulated in shell 116. An exemplary material for nanoparticle 114 isa soft-ferrite. Soft-ferrites, like other shunt materials, duct magneticflux without retaining any “after field.” An example of shell 116 isiron oxide, such as Fe₂O₃, which can be formed for example by chemicalvapor deposition (CVD) or atomic layer deposition (ALD). Another exampleof shell 116 is aluminum oxide, Al₂O₃, commonly referred to as alumina,which can be formed for example by chemical vapor deposition (CVD).Another example of shell 116 is a diamond-like film coating. Amorphous(a-C) and hydrogenated amorphous carbon (a-C:H) diamond-like films havehigh hardness, low friction, electrical insulation, chemical inertness,optical transparency, biological compatibility, ability to absorbphotons selectively, smoothness, and resistance to wear. Several methodshave been developed for producing diamond-like carbon films: primary ionbeam deposition of carbon ions (IBD); sputter deposition of carbon withor without bombardment by an intense flux of ions (physical vapordeposition or PVD); and deposition from an RF plasma, sustained inhydrocarbon gases, onto substrates negatively biased (plasma assistedchemical vapour deposition or PACVD). Silicon and Silicon Oxide, Si andSiO₂, may also be used for shell 116, which can be formed for example bychemical vapor deposition (CVD). Carbon nanotube 111 may contain asingle nanoparticle 113 or 114. Alternatively, carbon nanotube 111 maycontain multiple nanoparticles 113 or 114 and in any combinationthereof.

FIGS. 1-2 show Z axis along the length of nanotubes 101 and 111.Nanotubes 101 and 111 can either be Single-Walled carbon NanoTubes(SWNT) or Multi-Walled carbon NanoTubes (MWNT). MWNT's may be formedwith 2, 3, or more layers. The diameter D of nanotubes 101 and 111 ismeasured in nanometers. The diameter of the nanotubes, up to 12 nm,limits the size of nanoparticles 103-104 and 113-114. In addition tothose materials already mentioned, exemplary materials for magneticnanoparticles 103-104 or 113-114 include Cobalt (Co), Cobalt (Co) andtheir alloys, Cobalt-ferrite, Cobalt-nitride, Cobalt-oxide (Co—O),Cobalt-palladium (Co—Pd), Cobalt-platinum (Co—Pt), Iron (Fe), Iron (Fe)and their alloys, Iron-Gold (Fe—Au), Iron-Chromium (Fe—Cr), Iron-nitride(Fe—N), Iron-oxide (Fe₃O₄), Iron-palladium (Fe—Pd), Iron-platinum(Fe—Pt), Fe—Zr—Nb—B, Mn-nitride (Mn—N), Nd—Fe—B, Nd—Fe—B—Nb—Cu, Nickel(Ni), Nickel (Ni) and their alloys, and soft-ferrite. These magneticnanoparticles can be manufactured with sizes of 10 nm or less, such thatthese nanoparticles can fit within nanotubes 101 and 111. Examples ofsoft-ferrites include Mn—Zn, single crystal Mn—Zn, and Ni—Zn.

FIG. 3 shows magnetic storage medium 200. The T axis is along thethickness direction of magnetic storage medium 200. If magnetic medium200 is magnetic tape, then the L axis is along the length of the tapeand the W axis is along the width of the tape. Magnetic storage medium200 comprises substrate 201, data recording layer 202, and optionalshunt layer 203 in between substrate 210 and data recording layer 202.For magnetic tape and floppy disks, substrate 201 is typicallypolytetrafluoroethelyne (PTFE), which is commonly known by the tradename MYLAR™. For hard disks, substrate 201 can be aluminum, glass, or astiff plastic, such as polycarbonate.

Data recording layer 202 comprises a plurality magnetic carbon nanotubeassemblies 100 which are embedded in a polymer matrix, such as HDPE 230(High Density Poly Ethylene). Alternately, nanotube assemblies 100 arefirst encapsulated in HDPE and then embedded in a second polymericmatrix. Nanotubes 100 provide a home for nanoparticles 103-104 so theydo not clump into large masses within the data recording layer.Nanotubes 100 may be infused into matrix 230 while matrix 230 is in aliquid form. Matrix 230 may be then coated on to substrate 201 to formdata layer 202. As described in FIGS. 6-10, a magnet 601 may be used toorient nanotubes 100 within matrix 230 with respect to substrate 201.Once nanotubes 100 have been moved into a desired orientation by amagnetic field, matrix 230 may then be cured, thereby making theorientation of nanotubes permanent.

Shunt layer 203 comprises a plurality magnetic carbon nanotubeassemblies 110 which are embedded in a matrix comprising HDPE 231.Alternately, nanotube assemblies 110 are first encapsulated in HDPE andthen embedded in a second polymeric matrix. Nanotubes 110 provide a homefor the shunt nanoparticles 113-114, so they do not clump into largemasses within the shunt layer. Use of shunt layer 203 is optional, butit yields improved data recording when included in magnetic storagemedium 200. Nanotubes 110 may be infused into shunt matrix 231 whileshunt matrix 231 is in a liquid form. Matrix 231 may be then coated onto substrate 201 to form shunt layer 203. As described in FIGS. 6-10, amagnet 601 may be used to orient nanotubes 110 within shunt matrix 231with respect to substrate 201. Once nanotubes 100 have been moved into adesired orientation by a magnetic field, shunt matrix 231 may then becured, thereby making the orientation of nanotubes permanent.

Magnetic recording head 210 comprises write element 212 mounted on asoft ferrite matrix 211. Write element 212 is essentially a U-shapedpiece of low coercivity material and a wire coil, which forms anelectro-magnet. That portion of write element 212 adjacent to magneticstorage medium 200 is open, to allow magnetic flux 213 to leaverecording head 210 and penetrate magnetic storage medium 200 and imprintdata in the form of 1's and 0's based on the magnetic polarity of flux213. Shunt layer 203 completes the magnetic circuit (analogous tocompleting an electrical circuit) and keeps flux 213 from “fringing”excessively. Shunt layer 203 permits more crisp edge transitions, thuspermitting higher data densities on magnetic storage medium 200. Thus,data is stored in layer 202 with the assistance of shunt layer 203.Similarly, shunt layer 203 can assist in the reading of data. Writeelement 212 may further comprise a Metal-In-Gap (MIG) write head. Carbonnanotube assemblies 100 and 110 are positioned generally parallel to atop surface of substrate 201 and have a region of matrix materialpositioned between substrate 201 and carbon nanotube assemblies 100 and110, as shown in FIG. 3 with respect to axis W.

Data is read from magnetic storage medium 200, by means of anon-limiting example, via a magnetoresistive head, a spin-valve headwhich is alternately knows as a giant magnetoresistive “GMR” head, or atunnel magnetoresistive “TMR” head.

The process for forming magnetic storage medium 200 is to first applyshunt layer 203 onto substrate 201. This may be done as a thin monolayerof nanotubes by running magnetic tape through a solution of HDPE 231containing nanotubes 110. This may also be done as a thin monolayer ofnanotubes 100 by spin coating a solution of HDPE 231 containingnanotubes 100 onto a magnetic disk. Multiple shunt monolayers can belayered on top of the first monolayer forming shunt layer 203 throughrepeating this process. To maximize dispersal of nanotubes 100 and 110,ethylene or another material that disperses carbon nanotubes may beused.

Once shunt layer 203 is cured, which may include supplemental heating orcompression by rollers, data recording layer 202 is then added. This maybe done as a thin monolayer of nanotubes by running magnetic tapethrough a solution of HDPE 230 containing nanotubes 100, and then curingthe data layer 202. This may also be done as a thin monolayer ofnanotubes 100 by spin coating a solution of HDPE 230 containingnanotubes 100 onto a disk, and then curing the data layer. Multiple datarecording monolayers can be layered on top of the first monolayerforming data layer 202 through repeating this process. To maximizedispersal of nanotubes 100 and 110, ethylene another material thatdisperses carbon nanotubes may be used. Nanotubes 100 and 110 may becoated with an initial shell of HDPE before being added to HDPE 230 and231. Nanotube assemblies 100 and 110 are oriented generally parallel toa top surface of substrate 201.

FIG. 4 shows magnetic tape media 300 comprising substrate 301, magneticdata-recording layer 202, and shunt layer 203. The L axis is along thelength of tape 300, the W axis is along the width of the tape, and the Taxis is along the thickness of the tape. Tape media 300 has substrate301 typically formed of polytetrafluoroethelyne (PTFE), which iscommonly known by the trade name MYLAR™. Shunt layer 203 is formed onsubstrate 301. Shunt layer 203 is formed of a monolayer of shunt carbonnanotube assemblies 110. Assemblies 110 include carbon nanotubes 111containing nanoparticles 113 and 114. Carbon nanoparticle 113 has a lowor zero magnetic coercivity so that it does not permanently retain afirst magnetic field, which allows nanoparticles 103 to act as amagnetic shunt. Data recording layer 202 is formed of a monolayer ofcarbon nanotube assemblies 100. Assemblies 100 include carbon nanotubes101 which contain nanoparticles 103 and 104. Carbon nanoparticle 103 hasa high magnetic coercivity so that it can permanently retain a firstmagnetic field until that field is changed to a second magnetic field,allowing for data storage. Carbon nanotubes 101 and 111 are orientedsuch that they are generally parallel to the length wise direction tapemedia 300. Data tracks 303 are shown, from magnetic flux transitionsrecorded by magnetic head 210 in magnetic data-recording layer 202.

FIG. 5 shows magnetic disk 400 with monolayer rings 404 of layer 202 and203 formed in layers about the center 406 of disk 400. These layers maybe further masked into individual rings 404. Rings 404 may be formed asdistinct rings on disk 400 to form independent tracks. If disk 400 is ahard disk, substrate 402 can be aluminum, glass, or a stiff plastic,such as polycarbonate. If disk 400 is a floppy disk, substrate 402 istypically polytetrafluoroethelyne (PTFE), which is commonly known by thetrade name MYLAR™. Z is the direction perpendicular to the disk and theR axis is the radial direction. Shunt layer 203 is formed of a monolayerof shunt carbon nanotube assemblies 110. Assemblies 110 include carbonnanotubes 111 containing nanoparticles 113 and 114. Carbon nanoparticle113 has a low or zero magnetic coercivity so that it does notpermanently retain a first magnetic field, which allows nanoparticle 113to act as a magnetic shunt. Data recording layer 202 is formed of amonolayer of carbon nanotube assemblies 100. Assemblies 100 includecarbon nanotubes 101 which contain nanoparticles 103 and 104. Carbonnanoparticle 103 has a high magnetic coercivity so that it canpermanently retain a first magnetic field until that field is changedthat field is changed to a second magnetic field, allowing for datastorage. Carbon nanotubes 101 and 111 may be oriented such that theyextend radially from the center of disk 400. Alternatively, carbonnanotubes 101 and 111 may be oriented such that they extend in a spiralpattern from the center of the disk 400.

One method of forming rings 404 is through a photo-etching process.Layers 202 and 203 are first deposited onto disk 400 preferably througha spin coating process. A layer of photoresist material is thendeposited on top of layers 202 and 203. This layer of photoresist isexposed through a mask, thereby patterning layers 202 and 203. A removalprocess leaves the patterned layers 202 and 203. While shown as rings404, layers 202 and 203 may be patterned into any desirable track orsector pattern for data storage. Alternatively, when disk 400 is made ofpolycarbonate, rings 404 could be formed through a molding process. Atop surface of data recording layer 202 may further comprise buckyballs299, which would act to reduce friction between the recording layer 202and the magnetic head 210.

FIG. 6 illustrates the magnetically enhanced cure of magnetic tape toassist in the orientation of carbon nanotubes that encapsulate magneticnanoparticles. FIG. 7 illustrates the magnetically enhanced cure of amagnetic disk to assist in the orientation of carbon nanotubes thatencapsulate magnetic nanoparticles. By use of magnet 601, a constantmagnetic field is applied to the magnetic tape 300 and disk 400 toassist with the proper orientation of the nanotube assemblies 100 whiletape 300 and disk 400 is cured (polymer matrix 230 containing nanotubeassemblies 100 and 110 adheres to the substrate 201 and 301). Nanotubeassemblies 100 are free to move within polymer matrix 230 prior to thecuring of polymer matrix 230 as polymer matrix 230 is in a liquid, gel,or powdered state when initially applied to substrate 301 or 402. Matrix231 may also be applied in a liquid, get, or powdered state. Whennanotube assemblies 100 are free to move within polymer matrix 230,magnet 601 is able to assist in the orientation of nanotube assemblies100 with respect to magnetic tape 300 or disk 400 by applying a magneticfield that acts upon nanotube assemblies 100. Note that within apreferred embodiment, nanotube assemblies 100 are only present withindata tracks 303 and 404. In this preferred embodiment, the space betweendata tracks 303 and 404 is preferably void of any nanotube assemblies100. Magnet 601 is merely drawn in FIGS. 6 and 7 as being exemplary ofthe application of magnetism relative to magnetic tape 300 or disk 400.Specific magnet configurations that can create suitable field lines toproperly orient carbon nanotubes 101 as shown in FIGS. 8, 9 and 10 arewell known and exist in many varieties, and for example are disclosed inthe publication authored by Oleg D. Jefimenko, Electricity andMagnetism: An Introduction to the Theory of Electric and MagneticFields, second edition, (ISBN 0-917406-08-7), which is herebyincorporated by reference. Nanotube assemblies 100 preferably containmore than one nanoparticle 103/104 so that magnet 601 can magneticallyalign nanotubes 101.

By applying the magnetic field, magnet 601 is able to orient nanotubeassemblies 100 into a generally uniform orientation with respect tosubstrates 301 or 402. For example, magnet 601 may be manipulated withrespect to magnetic tape 300 to orient nanotube assemblies 100 parallelto the lengthwise axis of each data track. Alternatively, magnet 601 maybe manipulated with respect to magnetic tape 300 to orient nanotubeassemblies 100 perpendicular to the lengthwise axis of each data track.Magnet 601 may be manipulated with respect to disk 400 to orientnanotube assemblies 100 radially with respect to the center of disk 400.Alternatively, magnet 601 may be manipulated with respect to disk 400 toorient nanotube assemblies 100 parallel to the direction of data rings404 such that each nanotube is generally perpendicular the radial axisof disk 400. Please note that these orientations shown in this Figureare merely exemplary and any alignment of nanotubes is conceived. Magnet601, which may be either a permanent magnet or an electromagnet, exertsa constant magnetic field on tape 300 and disk 400 as the polymer matrixcures. If magnet 601 is a permanent magnet, it may be made out ofmagnetized soft iron. If magnet 601 is an electromagnet, then aelectrical coil (not shown) is wound around the ferrite body of magnet601 and when a DC current flows through this electrical coil, a magneticfield is created.

FIG. 8 illustrates a magnetic tape 300 having carbon nanotubes 101 invarious orientations within a data track 303. Magnet 601 can aligncarbon nanotubes 101 to an orientation 305 in which the longitudinalaxis of carbon nanotubes 101 is parallel to the lengthwise axis of datatrack 303. Alternatively, magnet 601 can align carbon nanotubes 101 toan orientation 306 in which the longitudinal axis of carbon nanotubes101 is rotated 45 degrees with respect to the lengthwise axis of datatrack 303. In addition, magnet 601 can align carbon nanotubes 101 to anorientation 307 in which the longitudinal axis of carbon nanotubes 101is perpendicular to the lengthwise axis of data track 303. The areas 304between each data track 303 may, in a preferred embodiment, be void ofany carbon nanotubes 101. In a preferred embodiment, shunt layer 203 isnot present in areas 304. A pair of parallel plates in a configurationlike a capacitor could generate a magnetic field between the plateshaving linear magnetic field lines that could create a magnetic fieldthat would orient nanotubes 101 in the manner shown in orientations 305,306, or 307. For example, having data tracks 303 run parallel to themagnetic field lines would create the orientation 305. Rotating datatracks 303 by 45 degrees with respect to the magnetic field lines wouldcreate the orientation 306. Positioning the data tracks 303 to runperpendicular to the magnetic field lines would create the orientation307. Please note that these magnet 601 and magnetic tape 300orientations are based upon the carbon nanotubes orienting themselvesparallel to the magnetic field lines. Also, please note that theseorientations shown in this Figure are merely exemplary and any alignmentof nanotubes is conceived.

FIG. 9 illustrates a magnetic disk 400 having carbon nanotubes 101 invarious orientations within an annular data track 404. Magnet 601 canalign carbon nanotubes 101 to an orientation 410 in which thelongitudinal axis of carbon nanotubes 101 is parallel to a tangent ofannular data track 404. For example, an isolated uniformly chargedsphere or rod placed at the center 406 of disk 400 would create magneticfield lines that would orient nanotubes 101 in the manner shown inorientation 410. Alternatively, magnet 601 can align carbon nanotubes101 to an orientation 412 in which the longitudinal axis of carbonnanotubes 101 is rotated 45 degrees with respect to a radial axis ofdisk 400. In addition, magnet 601 can align carbon nanotubes 101 to anorientation 408 in which the longitudinal axis of carbon nanotubes 101is aligned to a radial axis of disk 400. For example, a uniformlycharged rod extending through center 406 with a uniformly chargedcylinder surrounding disk 400 could create a magnetic field that wouldorient nanotubes 101 in the manner shown in orientation 408.Alternatively, placing a uniformly charged sphere at the center 406 andsurrounding disk 400 with another uniformly charged sphere could createmagnetic field lines that would orient nanotubes 101 in the manner shownin orientation 408. The areas 407 between each data track 404 may, in apreferred embodiment, be void of any carbon nanotubes 101. In apreferred embodiment, layer 202 is present only in data tracks 404.However, carbon nanotubes 111 may still be present within areas 407. Ina preferred embodiment, shunt layer 203 is not present in areas 407.Alternatively, shunt layer 203 may extend partially into areas 407 oneither side of data track 404 to prevent fringing at the boundaries ofdata track 404. Please note that these orientations shown in this Figureare merely exemplary and any alignment of nanotubes is conceived.

FIG. 10 illustrates a magnetic disk 400 having carbon nanotubes 101 invarious orientations within a spiral data track 414. Magnet 601 canalign carbon nanotubes 101 to an orientation 420 in which thelongitudinal axis of carbon nanotubes 101 is parallel to a tangent ofspiral data track 414. Alternatively, magnet 601 can align carbonnanotubes 101 to an orientation 418 in which the longitudinal axis ofcarbon nanotubes 101 is rotated 45 degrees with respect to a tangent ofspiral data track 414. In addition, magnet 601 can align carbonnanotubes 101 to an orientation 422 in which the longitudinal axis ofcarbon nanotubes 101 is perpendicular to a tangent of spiral data track414. The areas 416 between each data track 414 may, in a preferredembodiment, be void of any carbon nanotubes 101. In a preferredembodiment, layer 202 is present only in data tracks 414. Preferably,shunt layer 203 is not be present in areas 416 or shunt layer 203 mayextend partially into areas 416 on either side of data track 414 toprevent fringing at the boundaries of data track 414.

FIG. 11 illustrates a flow chart for manufacturing a magnetic disk 400having carbon nanotubes 101 and 111. This flow chart begins at START,step 1000. Substrate 402 for magnetic disk 400 is, in one embodiment, arigid substrate made for example of glass, aluminum, or an aluminumoxide. Substrate 402 is manufactured to have tracks 404 formed insubstrate 402 in step 1002. Tracks 404 may be formed, for example, by astamping process with a glass substrate. Alternatively, for example,tracks 404 may be formed through a photolithography process. Note thatfor FIGS. 11-16, tracks 414 may be substituted for tracks 404. Oncetracks 404 are formed, shunt matrix 231 containing shunt nanotubeassemblies 110 are deposited into tracks 404 to form layer 203 in step1004. Shunt matrix 231 may be in liquid, gel, or powered form. Duringthe deposition of shunt matrix 231 containing shunt nanotube assemblies110, substrate 404 may be vibrated to aid shunt matrix 231 with fillingtracks 404. Substrate 404 may be vibrated with subsonic, sonic, orultra-sonic vibrations. While being deposited, shunt matrix 231 ispreferably in a liquid state, or may be in a gel, or powdered state.Once shunt matrix 231 is deposited within tracks 404, shunt matrix 231is cured into a solid state. In step 1006, data recording matrix 230containing nanotube assemblies 100 is deposited into tracks 404 to formlayer 203. Substrate 402 is vibrated with subsonic, sonic, orultra-sonic vibrations to assist data recording matrix with fillingtracks 404. Data recording matrix 230 is preferably in a liquid statewhen deposited into tracks 404. As shown in FIGS. 13 and 14, a magneticfield created by magnet 602 may be used to draw nanotube assemblies 100out of a top portion 422 of the deposited data recording matrix 230 andconcentrate nanotube assemblies 100 in the lower portion 424 ofdeposited data recording matrix 230 within track 404. Also, as discussedabove, magnet 601 may be used to then align nanotubes 100 with respectto track 404. In addition, vibrating substrate 402 aids magnet 601 withorienting nanotubes 100 with respect to track 404. Once nanotubeassemblies 100 are oriented with respect to tracks 404, data recordingmatrix 230 is cured into a solid state, thereby forming layer 202. Instep 1008, layer 202 may be planarized to be flush with the sidewallsformed in substrate 402 that extend on either side of channel 404. Disk400 may then be optionally compressed. This process then terminates instep 1010.

FIG. 12 illustrates a cross-sectional flow diagram for manufacturing amagnetic disk 400 having carbon nanotubes 101 and 111 in accordance withthe process described in FIG. 11. In view A, tracks 404 are formed insubstrate 402 as described above in step 1002. Note that tracks 404 forma channel. In view B, shunt layer 203 is deposited within tracks 404 asdescribed above in step 1004. In view C, data recording layer 202 isdeposited within tracks 404 as described above in steps 1006 and 1008.

FIG. 13 illustrates a flow chart for manufacturing a data recordinglayer 202. The manufacturing process begins with step 2000 when liquiddata recording layer matrix 230 has been deposited on substrate 402 andwithin data tracks 404. Data recording matrix 230 may also be applied inpowered or gel form. In step 2002, a magnet 602, shown in FIG. 14,creates a magnetic field 428 through track 404 that acts upon nanotubeassemblies 100. Magnetic field 428 draws carbon nanotubes 100 alongpaths 426 from the upper portion 422 of data recording layer matrix 230down into the lower portion 424 of data recording matrix 230 withintrack 404, thereby creating an increased concentration of nanotubes 100within track 404. In step 2004, substrate 402 is then vibrated to aidthe data recording layer matrix 230 with filling track 404. In addition,vibrating substrate 402 aids magnet 601 with orienting nanotubes 100with respect to track 404. Once nanotubes 100 are in the properorientation, data recording matrix 230 is cured into a solid state, step2006, thereby forming layer 202. In step 2008, data recording layer 202may be planarized to be flush with the sidewalls formed in substrate 402that extend on either side of channel 404. Disk 400 may then beoptionally compressed. This process then terminates in step 2010.

FIG. 14 illustrates an exemplary formation of a data recording layer 202in accordance with the process described in FIG. 13. Magnet 602, isshown in this exemplary embodiment, to be positioned underneath datatrack 404. The magnetic field 428 generated by magnet 602 pullsnanotubes 100 down into track 404. Consequently, upper portions 422 ofdata recording matrix 230 have lower concentrations of nanotubes 100than lower portion 424 of data recording matrix 230 within track 404over shunt layer 203. Thus, this process increases the density of carbonnanotubes 100 within track 404 than otherwise existed in data recordingmatrix 230 when it was deposited.

FIG. 15 illustrates a flow chart for manufacturing a magnetic disk 400having carbon nanotubes 101 and 111. The process begins in step 3000. Ashunt barrier layer 430 is deposited over substrate 402 in step 3002.Shunt barrier layer 430 may be comprised of a shunt matrix 231 materialthat does not include nanotube assemblies 110.

Alternatively, shunt barrier layer 430 may be formed of an oxide,silicon, glass, or other material. Shunt barrier layer 430 is thenpatterned to form tracks 404 through a photolithographic process, astamping process, or other process capable of forming channels 404. Instep 3004, shunt matrix 231 containing shunt nanotubes 110 is depositedinto tracks 404 to form layer 203. Substrate 402 is then vibrated toassist the liquid shunt matrix 231 with filling tracks 404. Shunt matrix231 is then cured into a solid state to form layer 203. In step 3006,data recording matrix 230 containing nanotubes 100 is deposited intotracks 404 to form layer 202. Substrate 402 is sonically orsub-sonically vibrated to assist the liquid data recording matrix 230with filling tracks 404. In addition, substrate 402 is then vibrated toassist magnet 601 with orienting nanotubes 100 within tracks 404. Oncenanotubes 100 are oriented into a desired position, data recordingmatrix 230 is cured into a solid state thereby forming layer 202. Instep 3008, data recording layer 202 may be planarized to be flush withthe sidewalls formed in substrate 402 that extend on either side ofchannel 404. Disk 400 may then be optionally compressed. This processthen terminates in step 3010.

FIG. 16 illustrates a cross-sectional flow diagram for manufacturing amagnetic disk 400 having carbon nanotubes 101 and 111 in accordance withthe process described in FIG. 15. In view A, tracks 404 are formed insubstrate 402. In view B, shunt layer 203 is deposited within tracks404. In view C, data recording layer 202 is deposited within tracks 404.

FIG. 17 illustrates a flow chart for manufacturing a magnetic tape 300or a flexible magnetic disk 400 having carbon nanotubes 101 and 111. Theprocess being with step 4000. In step 4002, shunt matrix 231 containingshunt nanotubes 110 is printed onto substrate 301 or 402 to form tracks303 or 404. Shunt matrix containing shunt nanotubes 110 maybe in aliquid state that is then cured into a solid state to form shunt layer203, or a powder form that is then baked into a solid state to formshunt layer 203. In step 4004, data recording matrix 230 containingnanotubes 100 is printed on top of shunt layer 203 in tracks 303 or 404.Data recording matrix containing nanotubes 100 maybe in a liquid statethat is then cured into a solid state to form data recording layer 202,or a powder form that is then baked into a solid state to form datarecording layer 202. The process then ends in step 4006.

FIG. 18 illustrates a cross-sectional flow diagram for manufacturing amagnetic tape 300 or a flexible magnetic disk 400 having carbonnanotubes 100 or 101 in accordance with the process described in FIG.17. In view A, tracks 303 or 404 are formed by printing layer 203 onsubstrate 301 or 402. In view B, tracks 303 or 404 are further formed byprinting layer 202 on top of layer 203. Note that while shown printed ona substrate 301 or 402, ink containing carbon nanotubes 100 havingmagnetic particles may be printed on any other printable surface andused for applications that include, for example, RFID applications, barcodes, or other printed identifiers. In addition, carbon nanotubescontaining magnetic nanoparticles may be infused in a pattern in papercurrency to reduce the possibility of counterfeiting.

FIG. 19A illustrates a Hard Disk Drive (HDD) 5000. HDD 5000 is anon-volatile storage device that stores digitally encoded data on arotating magnetic disk 5016, which is an example of disk 400. Disk 5016is rotating clockwise in FIG. 19A, as designated by the curved arrow5016A. A control system 5010 controls the operation of HDD 5000. Aspindle motor 5036 supports one or a plurality of magnetic disks 5016.FIG. 19A shows a single disk 5016. However, it is contemplated thatmultiple disks 5016 may be vertically stacked in a column within HDD5000. Spindle motor 5036 may operate at a fixed speed or a variablespeed as measured in revolutions per minute (RPM). A magnetic read/writehead 5024 is mounted to the tip of arm 5030. Magnetic read/write head5024 reads digital data from and writes digital data to magnetic disk5016. A base 5026 of arm 5030 is provided with a slot 5028 that iscoupled to a piston 5032 that moves armature 5030 along a radial axis ofdisk 5016, thereby allowing read/write head 5024 to be positioned overany location on magnetic disk 5016 as disk 5016 rotates underneath. Disk5016 is shown next to coordinate axis T and R which show the tangentialand radial axis directions with respect to disk 5016 respectively.Piston 5032 is typically an electromagnet, but could alternately bepneumatic, hydraulic, or electrostatic. Disk 5016 is an example of disk400.

It is desirable to control the distance between read/write head 5024 anddisk 5016 to optimize the ability of read/write head 5024 to write andread magnetic polarities on disk 5016. One method of controlling thedistance between read/write head 5024 and disk 5016 is by formingarmature 5030 of a piezoelectric ceramic. When armature 5030 is formedof a piezoelectric material, the distance between read/write head 5024and disk 5016 is controlled by controller 5010 by applying an electricfield to the piezoelectric ceramic causing armature 5030 to deform,thereby positioning read/write head 5024 at a desired distance from disk5016. The piezoelectric effect is reversible in that materialsexhibiting the direct piezoelectric effect (the production of anelectric potential when stress is applied) also exhibit the reversepiezoelectric effect (the production of stress and/or strain when anelectric field is applied). For example, lead zirconate titanatecrystals, (Pb[Zr_(x)Ti_(1-x)]O₃ 0<x<1), more commonly known as PZT, willexhibit a maximum shape change of about 0.1% of the original dimension.Lead zirconate titanate is a common piezoelectric ceramic that may beused for armature 5030. Other piezoelectric ceramic materials includebarium titanate (BaTiO₃), lead titanate (PbTiO₃), potassium niobate(KNbO₃), lithium niobate (LiNbO₃), lithium tantalate (LiTaO₃), sodiumtungstate (Na₂WO₃), Ba₂NaNb₅O₅, and Pb₂KNb₅O₁₅.

When spindle motor 5036 rotates disk 5016, disk 5016 may wobble aboutits central axis. This wobble may be compensated for with control system5010 by synchronously varying the distance between armature 5030 anddisk 5016. One exemplary model of a wobbling disk 5016 that may be usedby control system 5010 for controlling piezoelectric armature 5030 tocompensate for the wobbling of disk 5016 is given below by Equation 1:

Z _(wobble) =H _(w)*(r/R _(o))*sin(w*t+phi)  EQN. [1]

H_(w) is the maximum amplitude of the wobble of disk 5016 caused by disk5016 spinning at an angle offset from the vertical, or another datumangle. H_(w) is measured at R_(o). Note Z_(wobble) increases withincreasing I/O radius r.

r=radius of where I/O being performed, Rin≦r≦Ro

Ro=Radius of outer track

Phi=phase angle relative to marker radial line (or arc)

w=RPM of disk

t=time

Note that w*t is equal to an angle of rotation Theta, which may besubstituted for in Equation 1.

It is desirable for disk 5016 to have the configuration of a flat disk.However, it is contemplated that disk 5016 may be partially distortedwhen manufactured forming, for example, a cone shape. An exemplary modelthat may be used by controller 5010 for controlling armature 5030 for acone shaped disk is given below by Equation 2. Note Z_(cone) increaseswith increasing I/O radius r. Z_(cone) at zero radius is zero becausedisk 5016 is attached at its center. Therefore the center of disk 5016becomes the elevation datum.

Z _(cone) =−H _(c) *[r/Ro]  EQN. [2]

H_(c)=Cone height. H_(c) may be positive for a concave cone or negativefor a convex cone. H_(c)=zero for a perfectly flat disk. A thirdexemplary model that may be used by controller 5030 for controllingarmature 5030 that compensates for both wobbling of disk 5016 and acone-shaped distortion of disk 5016 is given below by Equation 3.

Z _(total) =Zwobble+Z _(cone)  EQN. [3]

Z_(total) may be found, for example, by taking several measurements,such as every 45 degrees along disk 5016, and doing a least squares fit.Disk 5016 may include various other positional and structuralnon-idealities similar to those described above that may be similarlycompensated for by other analogous models.

Control system 5010 includes a read/write channel 5012 that controls theoperation of read/write head 5024, as depicted by the double-arrowedbi-directional communication line between channel 5012 and read/writehead 5024. In addition, channel 5012 communicates data to read/writehead 5024 during write operations and receives read data from read/writehead 5024 during read operations. Drive circuit 5014 controls themechanical operation of spindle motor 5036 and the movement of arm 5030along the radial axis of disk 5016 in order to position read/write head5024 over disk 5016 to enable read and write operations. Suchpositioning of read/write head 5024 is sometimes referred to a “seek.”In addition, controller 5010 may receive feedback from motor 5036 andpiston 5032. Further, controller 5010 may apply an electric field toarmature 5030 to cause a piezoelectric material forming armature 5030 todeform in order to optimize the distance between read/write head 5024and disk 5016.

Disk 5016 includes a data layer 202 as shown in FIG. 3. Disk 5016 mayoptionally also include a shunt layer 203 and a substrate 201. Datalayer 202 faces read/write head 5024 and is organized into a pluralityof data sectors 5017. Substrate 201 is furthest from read/write head5024, and shunt layer 203, if used, is sandwiched between data layer 202and substrate 201. A data sector 5017 is a portion of disk 5016 definedby two nonequal radii extending from the center of disk 5016, and acorresponding angle, forming what is mathematically defined as a sectorof an annulus. Each data sector 5017 may be placed between two servosectors 5020. Each data sector 5017 includes a plurality of data blocks5018 that may be organized in concentric circular tracks 5019, and thereis an integral number of data blocks 5018 in a circular track 5019.However, data blocks 5018 could be laid out on a single spiral. Disk5016 is referred to as “banded” as the three outermost tracks 5019 ofdisk 5016 have 14 data blocks 5018 while the four innermost tracks 5019of disk 5016 have 7 data blocks 5017. The four innermost tracks 5019 ofdisk 5016 are referred to as data band 0 because each has seven datablocks, and the three outermost tracks 5019 of disk 5016 are referred toas data band 1 as each has fourteen data blocks. The number of datablocks 5018 and data tracks 5019 and data sectors 5017 shown in FIG. 19Ais merely exemplary and is not intended to be limiting. It iscontemplated that disk 5016 may include any number or combination ofdata sectors 5017, data blocks 5018 and data tracks 5019. In addition,the number of servo sectors 5020 shown in FIG. 19A is merely exemplaryand non-limiting. It is contemplated that disk 5016 may include anynumber of servo sectors 5019. Disk 5016 is shown FIG. 19A as beingformatted as banded media. The band zero includes one data block 5018per data sector 5017. Band zero includes the four inner tracks 5019. Thefirst band includes two data blocks 5018 per data sector 5017. The firstband includes the three outermost data tracks 5019. FIG. 19A is merelyan exemplary implementation of banded media, which may include fewer orgreater numbers of data blocks 5018 per each track 5019 and sector 5017.The number of data blocks per revolution is given by Equation 4 below.

Number of Data Blocks Per Revolution=(m+1)*N  EQN. [4]

m=data band number

N=number of servo sectors on disk

Each data block 5018 is provided with a data header 5034, which istypically read first before the data in data block 5018 is accessed.Data band zero is further described as the data blocks 5018 in thefirst, second, third and fourth tracks 5019 nearest the center of disk5016 that each contain one data block 5018 per data sector 5017. Thedata block in the first track nearest the center of disk 5016 arelabeled 5018A. The data blocks in the second track 5019 are labeled5018B. The data blocks in the third track 5019 are labeled 5018C. Thedata blocks in the fourth track 5019 are labeled 5018D. Data band one isfurther described as the fifth, sixth, and seventh tracks 5019 each havetwo data blocks 5018 per data sector 5017. The two data blocks in thefifth data track 5019 are labeled 5018E1 and 5018E2. The two data blocksin the sixth data track 5019 are labeled 5018F1 and 5018F2. The two datablocks in the seventh data track 5019 are labeled 5018G1 and 5018G2.Data tracks 5019 are tangentially aligned to disk 5016.

Data sectors 5017 are pie shaped wedges on disk 5016 that are positionedin between servo sectors 5020. Servo sectors 5020 are formed during themanufacture of disk 5016 and remain a permanent part of disk 5016. Servosectors 5020 include grey code that provides positioning information tocontroller 5010 to position arm 5030 over disk 5016. Rotationalreference marker 5022 is associated with one of the servo sectors 5022to indicate which servo sector 5020 is the first servo sector 5020.Rotational reference marker 5022 may include grey code. Data headers5034 include grey code and may also include a sector and track numberthat identifies each data block 5018.

Data blocks 5018, data headers 5034, servo sectors 5020, and marker 5022are all formed of arrays of nanotube assemblies 110 that containmagnetic nanoparticles 103 or 104. Disk structures 5018, 5020, 5022, and5034 may have nanotube assemblies 110 that contain nanoparticles thathave differing coercivities unique to the individual disk structure5018, 5020, 5022, and 5034. Additionally, non-magnetic nanoparticles maybe used in any combination with the magnetic nanoparticles formingstructures 5018, 5020, 5022, and 5034. In one embodiment of thedisclosure, servo sectors 5020 are formed with nanotube assemblies 110that are filed with nanoparticles 103 or 104 that have a highercoercivity than the nanoparticles forming data blocks 5018. Since servosectors 5020 are permanent features of disk 5016, it is desirable thatthey are made of a higher coercivity material. Data blocks 5018 are madeof lower coercivity nanoparticles 103 or 104, which are easier to writeto with read/write head 5024. It is desirable that marker 5022 be madeof nanotube assemblies 110 having nanoparticles 103 or 104 that have ahigher coercivity than the nanoparticles 103 or 104 forming data blocks5018, but a lower coercivity than the nanoparticles forming servosectors 5020. It is also desirable that data headers 5034 be made ofnanotube assemblies 110 having nanoparticles 103 or 104 that have ahigher coercivity than the nanoparticles of data blocks 5018, but alower coercivity than the nanoparticles of maker 5022 or servo sector5020. It is desirable to utilize nanoparticles 103 or 104 that havedifferent levels of coercivity to form the different structures 5018,5020, 5022, and 5034 on disk 5016 to enhance the performance of theirrespective different functions. Alternatively, it is envisioned that allstructures 5018, 5020, 5022, and 5034 be made of nanoparticles 103 or104 that have the same level of coercivity. It is also contemplated thatany one or more individual disk structures 5018, 5020, 5022, or 5034 maybe made with nanoparticles 103 or 104 having a different coercivity fromthe other structures 5018, 5020, 5022, or 5034 on disk 5016. Forexample, servo sectors 5018 may be made of nanoparticles 103 or 104 thathave a higher coercivity than data blocks 5018. However, rotationalreference marker 5022 may be made of nanoparticles 103 or 104 that havethe same coercivity as servo sectors 5020. In addition, data headers5034 may be made of nanoparticles 103 or 104 that have the samecoercivity as data blocks 5018. Any combination of difference ofcoercivity of nanoparticles is contemplated for each disk structure5018, 5020, 5022, and 5034. Exemplary and non-limiting ranges ofcoercivity and materials for each disk structure 5018, 5020, 5022, and5034 are provided below in Table 1. Rotational reference marker 5022 maybe formed of a single nanotube assembly 110 containing nanoparticleshaving a high coercivity. Alternatively, rotational reference marker5022 may be formed of multiple nanotube assemblies 110. An exemplary andnon-limiting range of coercivities for disk structures 5018, 5020, 5022,and 5034 is provided below in Table 1 for a disk 5016 having anexemplary non-limiting coercitivity range of 0.5 T to 3.0 T, where T isTesla. Disk 5016 and disk structures 5018, 5020, 5022, and 5034 may haveoverlapping or non-overlapping ranges of coercivities that exceed thoseshown in Table 1. Additional exemplary and non-limiting coercivityranges for disk structures 5018, 5020, 5022, and 5034 are provided belowin Tables 2 and 3. The coercivities of exemplary nanoparticles that maybe used for disk structures 5018, 5020, 5022, and 5034 are providedbelow in Table 4.

TABLE 1 First Exemplary Coercivity Ranges for Disk 5016 StructuresExemplary Coercivity Disk 5016 Structure Range (Tesla T) Servo Sector5020 0.300 T-0.225 T Marker 5022 0.250 T-0.200 T Data Header 5034 0.200T-0.100 T Data Block 5018 0.175 T-0.050 T

TABLE 2 Second Exemplary Coercivity Ranges for Disk 5016 StructuresExemplary Coercivity Disk 5016 Structure Range (Tesla T) Servo Sector5020 2.25 T-1.50 T Marker 5022 2.00 T-1.25 T Data Header 5034 1.50T-0.50 T Data Block 5018 0.150 T-0.01 T 

TABLE 3 Third Exemplary Coercivity Ranges for Disk 5016 ExemplaryCoercivity Disk 5016 Structure Range (Tesla T) Servo Sector 5020 0.200T-0.125 T Marker 5022 0.150 T-0.100 T Data Header 5034 0.125 T-0.075 TData Block 5018 0.125 T-0.050 T

TABLE 4 Exemplary Nanoparticles and Their Associated CoercivitiesMaterial Coercivity (T) BaFe₁₂O₁₉ 0.36 Alnico IV 0.07 Alnico V 0.07Alcomax I 0.05 MnBi 0.37 Ce(CuCo)₅ 0.45 SmCo₅ 1 Sm₂Co₁₇ 0.6 Nd₂Fe₁₄B 1.2FePt 1.0 CoPt 0.23-2.4 Co₂FeO₄ 0.68-2.2 Fe₃C, Fe₃O₄, α-Fe 0.027-0.2 NanoCAP (Disclosed in the publication, which is 0.3 hereby incorporatedby reference in its entirety: (Sasaki, Usuki, Matsuo, and Kishimoto:Development of NanoCAP (Nano Composite Advanced Particles) Technologyfor High Density Recording, Development and Technology Division, HitachiMaxell, Kyoto, Japan; IEEE Transactions on Magnetics, Vol. 41, No. 10,October 2005, pages 3241-3243)

FIG. 19B illustrates a diagram of a magnetic disk 5076 that has datatracks 5080 and servo sector 5082 arranged in a ‘gentle-arc’configuration. This ‘gentle-arc’ configuration is used in combinationwith a read/write head 5024 which is pivotally mounted relative to pivot5073. Read/write head 5024 is mounted to arm 5072 that is pivotallyattached to a DC electromagnetic motor 5074. The rotation of disk 5076and pivoting of arm 5072 back and forth along direction 5072A iscontrolled by drive circuit 5014. A motor for spinning disk 5076supports disk 5076 at the center 5078 of disk 5076. Read/write channel5012 controls read/write head 5024 and transmits data to be written todisk 5076 by read/write head 5024, or receives data read from disk 5076.The configuration of the ‘gentle-arc’ of data tracks 5080 and servotrack 5082 matches the arcing path of read/write head 5024 as read/writehead 5024 is pivoted on arm 5072 by motor 5074. Data tracks 5080 extendfrom the inner radius of disk 5076 to the outer radius of disk 5076 in agentle-arc. Motor 5074 is typically an electromagnet. A spacer region5084 is provided between the center of disk 5078 and servo sector 5082.Data headers 5086 are provided for identifying each data block 5080. Arotational marker 5083 is provided to identify the first servo sector5082. Armature 5072 may also be made of a piezoelectric material that isdeformed by application of an electric field by controller 5010 in orderto control the distance between read/write head 5024 and disk 5076.

As discussed above with respect to disk 5016, servo sectors 5082, marker5083, data blocks 5080, and data headers 5086 all include nanotubeassemblies 110. However, each of these structures 5082, 5083, 5080, and5086 may include nanotube assemblies 110 that are filled withnanoparticles 103 or 104 that have different coercivities. For example,it is desirable that servo sector 5082 have nanoparticles that have ahigher coercivity than the nanoparticles forming data headers 5086 ordata blocks 5080. It is also desirable to that data headers 5084 beformed of nanoparticles that have a higher coercivity than thenanoparticles that form data blocks 5080. In addition, it is desirablethat marker 5083 have nanoparticles that have a higher coercivity thanthe nanoparticles forming data header 5086 or data blocks 5080, but thatalso have a lower coercivity than the nanoparticles forming maker 5083.Exemplary and non-limiting ranges of coercivity and exemplary particlesfor these structures are given above in Tables 1, 2, and 3. Exemplarynanoparticles are shown above in Table 4. Disk 5076 rotates in direction5076A.

FIG. 19C illustrates a diagram of a magnetic disk 6000 that has datatracks 6002 arranged tangentially about the center 6004 of disk 6000.Disk 6000 also includes servo sectors 6006 that are arranged in a‘gentle-arc’ configuration. This ‘gentle-arc’ configuration is used incombination with a read/write head 5024 which is pivotally mountedrelative to pivot 5073. Read/write head 5024 is mounted to arm 5072 thatis pivotally attached to a DC electromagnetic motor 5074. The rotationof disk 6000 and pivoting of arm 5072 is controlled by drive circuit5014. A motor for spinning disk 6000 supports disk 6000 at the center6004 of disk 6000. Read/write channel 5012 controls read/write head 5024and transmits data to be written to disk 6000 by read/write head 5024,or receives data read from disk 6000. The configuration of the‘gentle-arc’ of servo track 6006 matches the arcing path of read/writehead 5024 as read/write head 5024 is pivoted on arm 5072 by motor 5074.The direction of pivot is shown by arrow 5072A. Data tracks 6002 extendtangentially around disk 6000. Motor 5074 is typically an electromagnet.A rotational marker 6008 is provided to identify the first servo sector6006. Each data track 6002 may include multiple data sectors 6010, aswith disk 5016 in FIG. 19A. Each data sector may include one or moredata blocks 6012. Data headers 6014 are provided for identifying eachdata block 6012. Disk 6000 rotates in direction 6000A.

As discussed above with respect to disk 5016, servo sectors 6006, marker6008, data blocks 6012 and data headers 6014 all include nanotubeassemblies 110. However, each of these structures 6006, 6008, 6012, and6014 may include nanotube assemblies 110 that are filled withnanoparticles 103 or 104 that have different coercivities. For example,it is desirable that servo sector 6006 have nanoparticles that have ahigher coercivity than the nanoparticles forming data headers 6014 ordata blocks 6012. It is also desirable to that data headers 6014 beformed of nanoparticles that have a higher coercivity than thenanoparticles that form data blocks 6012. In addition, it is desirablethat marker 6008 have nanoparticles that have a higher coercivity thanthe nanoparticles forming data header 6014 or data blocks 6012, but thatalso have a lower coercivity than the nanoparticles forming maker 6008.Exemplary and non-limiting ranges of coercivity and exemplary particlesfor these structures are given above in Tables 1, 2, and 3. Exemplarynanoparticles are shown in Table 4.

Each data block 6012 is provided with a data header 6014, which istypically read first before the data in data block 6012 is accessed.Data band zero is described as the data blocks 6012 in the first,second, third and fourth tracks 6002 nearest the center of disk 6000that each have one data block 6012 per data sector 6010. The data blockin the first track nearest the center 6004 of disk 6000 are labeled6012A. The data blocks in the second track 6002 are labeled 6012B. Thedata blocks in the third track 6002 are labeled 6012C. The data blocksin the fourth track 6002 are labeled 6012D. Data band one is furtherdescribed as the fifth, sixth, and seventh tracks 6002 that each havetwo data blocks 6012 per data sector 6010. The two data blocks in thefifth data track 6002 are labeled 6012E1 and 6012E2. The two data blocksin the sixth data track 6002 are labeled 6012F1 and 6012F2. The two datablocks in the seventh data track 6002 are labeled 6012G1 and 6012G2.Data tracks 6002 are tangentially aligned to disk 6000.

FIG. 20 illustrates a perspective view of a read/write head 5024 havinga “Y” shaped cantilevered piezoelectric nanostructure read-head 5052 anda carbon nanotube write-head 5042. FIG. 20 illustrates a bottom portion5038 of read/write head 5024 that is placed adjacent to magnetic disk5016 and data layer 202, as shown in FIGS. 19A-C. Detailed views ofread-head 5052 are provided in FIGS. 21 and 24. A detailed view ofwrite-head 5042 is provided in FIG. 23. Read-head 5052 and write-head5042 are controlled by controller 5010 (FIGS. 19A-C) through read/writechannel 5012. Blocks 5040 and 5046 provide mechanical protection towrite-head 5042, such as wear resistance and mechanical spacing.Write-head 5042 is a device that generates a magnetic field sufficientto magnetically polarize magnetic nanoparticles 103 or 104 within a dataheader 5034/5086 or a data block 5018/5080. Write-head 5042 is formed ofa carbon nanotube 101 containing magnetic nanoparticles 103/104 (shownin FIG. 23) that is generally configured into a “C” shape having a gap5044 from which a magnetic field is emitted. A nanowire 5060 (shown inFIG. 23) is wrapped around the carbon nanotube 101 forming an inductiveelement that generates a magnetic field in gap 5044. Write-head 5042magnetically polarizes magnetic nanoparticles 103/104 within data layer202. Read/write head 5024 is aligned to track along data blocks 5018,5080, and 6002, as shown by arrow 5043, such that write element 5042tracks along data blocks 5018, 5080, and 6002 before read element 5052.This configuration allows for the write-verification of data that iswritten by write head 5042 by reading the written data with read head5052. In addition, the “Y” shaped nanostructure forming read element5052 is preferably pointed along the direction of movement 5043 ofread/write head 5024 so that read head 5052 is not placed into abuckling condition with the rotation of disk 5016, 5076, or 6000.

Read-head 5052 detects the magnetic polarization of magneticnanoparticles 103/104 within data layer 202. Read-head 5052 is comprisedof a “Y” shaped nanostructure 5052. FIG. 21 illustrates a perspectiveview of a read-head 5052 having a “Y” shaped nanostructure 5052. The “Y”shaped nanostructure includes two base ends 5058 and a probe end 5056.Each of the base ends 5058 are electrically connected to an electricalcontact 5054. Electrical contacts 5054 are supported on surface 5048 andare in communication with read/write channel 5012 of controller 5010.Probe tip 5056 is bent downward toward a top surface of magnetic disk5016 in order to be in sufficient proximity of the magnetic disk 5016 tointeract with the magnetic polarization of magnetic nanoparticles103/104 within data layer 202. Raised portion 5050 provides mechanicalprotection to the “Y” nanostructure 5052. “Y” shaped nanostructure isconfigured to interact with the polarization of magnetic nanoparticles103/104 within data layer 202. Probe tip 5056 contains magneticnanoparticles 103/104, as shown in FIG. 24. The magnetic polarization ofmagnetic nanoparticles 103/104 within data layer 202 interacts withmagnetic nanoparticles 103/104 within probe tip 5056 causing probe tip5056 to either be deflected towards or away from the magnetic diskdepending if they have the same or different magnetic polarization. Thisdeflection in probe tip 5056 causes a change in the conductivity of “Y”shaped nanostructure 5052 across base ends 5058 that indicates themagnetic polarization of the magnetic nanoparticles within data layer202. The changes in conductivity of “Y” shaped nanostructure 5052 aremeasured across contacts 5054 and communicated to controller 5010through read/write channel 5012. While shown in a “Y” configuration,this configuration of read-head 5052 is merely exemplary and is notlimiting. Read-head 5052 may be formed of carbon nanotube structuresformed having an “X” configuration, a “V” configuration, a “T”configuration, a “W” configuration, or may be formed of a simplenanotube employed as a cantilever beam.

FIG. 22 illustrates a side view of a read/write head 5024 having a “Y”shaped nano structure read-head 5052 and a carbon nanotube write-read5042. Note that base ends 5058 of nanostructure 5052 are parallel to thesurface of contacts 5054. Probe tip 5056 is bent down toward the topsurface of a magnetic disk in order to magnetically interact with themagnetic polarization of magnetic nanoparticles 103/103 within datalayer 202. Write-head 5042 and read-head 5052 and blocks 5040, 5046, and5050 are positioned such that they are generally the same distance fromthe top surface of a magnetic disk when read/write head 5024 ispositioned over a magnetic disk. The direction of movement 5043 ofread/write head 5024 is shown. The direction of movement 5043 means thatwrite head 5042 encounters the media before read head 5052. Thisdirection of movement 5043 allows of write-verify operations where readhead 5052 reads what write head 5042 just wrote.

FIG. 23 illustrates a magnetic field generator 5042 formed of a shapedcarbon nanotube 101 that contains a plurality of magnetic nanoparticles103/104. Carbon nanotube 101 is shown in a “C” shape configuration. Theuse of a “C” configuration is merely exemplary. Carbon nanotube 101 mayalso be formed in a “U” shaped or “horseshoe” shaped configuration.Carbon nanotube 101 is filed with nanoparticles 101 made of asoft-ferrite material that conducts and directs magnetic flux induced bynanowire 5060. The direction of magnetization of soft-ferrites is easilyreversed without dissipating much energy (hysteresis losses) due to thelow coercivity of soft-ferrites. In addition, soft-ferrites typicallyhave a high resistivity that prevents eddy currents in the core, whichis another source of energy loss in switching direction of the magneticfield. This ability to easily reverse the direction of magnetizationsupports the write function of generator 5042. Most modern magneticallysoft ferrites have a cubic (spinel) structure. The general compositionof such ferrites is MeFe₂O₄, where Me represents one or several of thedivalent transition metals such as manganese (Mn), zinc (Zn), nickel(Ni), cobalt (Co), copper (Cu), iron (Fe) or magnesium (Mg). The mostpopular combinations are manganese and zinc (MnZn) or nickel and zinc(NiZn). Other soft ferrites includes Ni₄₅Fe₅₅, and Ni₈₀Fe₂₀. Thesecompounds exhibit good magnetic properties below a certain temperature,called the Curie Temperature (T_(C)). They can easily be magnetized andhave a rather high intrinsic resistivity. These materials can be used upto very high frequencies without laminating, as is the normalrequirement for magnetic metals. NiZn ferrites have a very highresistivity and are most suitable for frequencies over 1 MHz, however,MnZn ferrites exhibit higher permeability (μ_(i)) and saturationinduction levels (B_(S)) and are suitable up to 3 MHz. For certainspecial applications, single crystal ferrites can be produced, but themajority of ferrites are manufactured as polycrystalline ceramics.

A space 5044 is located at the opening of the “C” shape configuration ofcarbon nanotube 101. Space 5044 has a distance marked “D.” The distance“D” of space 5044 corresponds to an area of a data layer 202 on to whichwrite-head 5042 can write data. It is desirable that space 5042 have aseparation distance “D” that is at least large enough to magneticallypolarize a single magnetic nanoparticle 103/104 within data layer 202.Carbon nanotube 101 is wrapped with a nanowire 5060. Nanowire 5060 formsan inductive element when it is wrapped in a coil around carbon nanotube101, thereby creating a magnetic field within space 5044. Examples ofmaterials for nanowires include Ni (Nickel), Pt (Platinum), and Au(Gold).

FIG. 24 illustrates a “Y” shaped nanostructure 5052 forming a componentof a read-head 5052. Base portions 5058 and probe tip 5056 are formed ofcarbon nanotubes 101. An end of probe tip 5056 includes magneticnanoparticles 103/104 in order to enhance the ability of probe tip 5056to interact with the magnetic polarization of nanoparticles 103/104present within data layer 202. “Y” shaped nanostructure 5052, which is acantilevered piezoelectric nanostructure, may be formed of a singlebranching carbon nanotube. Carbon nanotubes 101 possess piezoelectricproperties that allow for the internal detection of the movement ofcantilevered carbon nanotubes such as “Y” nanostructure 5052 acrosselectrodes 5054. While shown in a “Y” configuration, it is contemplatedthat nanostructure 5052 may also have a “V,” “T,” or “X” configuration.A more detailed description of cantilevered carbon nanotube probes isprovided in U.S. Pat. No. 7,462,270 entitled “Cantilever Probes forNanoscale Magnetic and Atomic Force Microscopy,” issued on Dec. 9, 2008,which is hereby incorporated by reference in its entirety. Nanostructure5052 and controller 5010 are configured to operate to read binary data.Thus, nanostructure 5052 is required to at least provide sufficientpiezeoelectric response to indicate a positive or negative magneticpolarization upon at least one magnetic nanoparticle 103/104.

FIG. 25 illustrates a side view of a read/write head 5024 having amagnetic force microscopy probe read-head 5062. Magnetic ForceMicroscopy (MFM) probe read-head 5062 derives from an Atomic ForceMicroscope (AFM). When an AFM is augmented with a magnetized tip 5066which is used to detect the magnetic polarization of magneticnanoparticles 103/104, and thus, the tip-sample magnetic interactionsare detected, this augmented structure is called a MFM. In MFMmeasurements, the magnetic force F between the sample and tip can bedescribed by:

F=μ _(o)(m*∇)H  Equation 1

where m is the magnetic moment of the tip (approximated as a pointdipole), H is the magnetic stray field from the sample surface, andμ_(o) is the magnetic permeability of free space. MFM resolutions as lowas 10 to 20 nm are attainable with permanent magnets. It is possible toincrease this resolution by using an electromagnet on the tip 5066. Tip5066 is suspended on cantilever 5064. Cantilever 5064 can be formed ofany material capable of deflecting under the magnetic interaction ofprobe tip 5066 with polarized magnetic nanoparticles 103/104 within datalayer 202, such as carbon nanotubes, or thin sheets of metal, plastic,piezeoelectric ceramic, or other composite material. The deflection ofthe probe tip 5066 on cantilever 5064 is optically measured by anoptical detector 5067 contained within read/write head 5024. Probe head5062, optical detector 5067 and controller 5010 are configured to readbinary data on a magnetic disk. Thus, probe head 5062, optical detector5067 and controller 5010 are at least required to determine positive andnegative magnetic polarizations of magnetic nanoparticles 103/104contained within data layer 202. Cantilever 5064 is preferablypositioned such that tip 5066 points along the direction of movement5043 of read/write head 5024, thereby preventing cantilever 5064 frombeing placed in a buckling position with respect to disk 5016, 5076, or6000.

FIG. 26 illustrates a perspective view of a read/write head 5024 havinga magnetic force microscopy probe read-head 5064. Note how probe tip5066 is suspended from cantilever 5064 that is attached to surface 5048,as shown in FIG. 25. Blocks 5050 and 5046 are provided for mechanicalprotection of read-head 5064. The probe tip 5066, blocks 5050, 5046, and5040, and write-head 5042 are all positioned to generally have the sameheight above the top surface of a magnetic disk when read/write head5024 is positioned above a magnetic disk. Read/write head 5024 isaligned to track along data blocks 5018, 5080, and 6002, as shown byarrow 5043, such that write element 5042 tracks along data blocks 5018,5080, and 6002 before read element 5066. This configuration allows forthe read-verification of data that is written by write head 5042. Inaddition, the cantilever 5064 and tip 5066 forming the read element 5062is preferably pointed away from the direction of movement of read/writehead 5024 so that read head 5062 is not placed into a buckling conditionwith the rotation of disk 5016, 5076, or 6000. Cantilever 5064 may beformed of a polymer, metal, ceramic, composite material, or one or morecarbon nanotubes, for example.

FIGS. 27-29 illustrate a write head formed of a Helmholtz coil. AHelmholtz coil is formed of two identical circular magnetic coils thatare placed symmetrically one on each side of the area of a magnetic disk400 or tape 300, shown in FIG. 29, to which data is to be written toalong a common axis, and separated by a distance h equal to the radius Rof the coil. Each coil carries an equal electrical current flowing inthe same direction. Setting h=R, which is what defines a Helmholtz pair,minimizes the nonuniformity of the field at the center of the coils.FIG. 27 illustrates a single coil 5068 forming one-half of a Helmholtzcoil pair that includes a nano-wire 5070 wrapped around a bobbin 5072formed of a carbon nanotube. Carbon nanotubes can be formed having theproperties of a metal, a semiconductor, or an insulator. Bobbin 5072 isformed of a non-conducting carbon nanotube that has the properties of aninsulator. Nanowire 5070 is shown wrapped around bobbin 5072 once.However, this embodiment is merely exemplary and nanowire 5070 may bewrapped multiple times around bobbin 5072. Examples of materials fornanowires include Ni (Nickel), Pt (Platinum), and Au (Gold).

FIG. 28 illustrates a perspective view of a read/write head 5024 showinga portion 5068 of a write-head formed of a Helmholtz coil. A bottomportion 5038 of read/write head 5024 is shown. As discussed above, twosuch coils 5068 are required to form a Helmholtz coil. Blocks 5040 and5046 provide mechanical protection to coil 5068. In this Figure,write-coil 5068 is shown together with read-head 5052 merely forexemplary purposes. It is also contemplated that write-head 5068 may becoupled with read-head 5062. Blocks 5040, 5046, and 5050 are positionedtogether with write-head 5068 and read-head 5052 in such a manner thatall of these features are generally the same distance from the topsurface of a magnetic disk when read/write head 5024 is positioned overa disk 300, or tape 400, as shown in FIG. 29. Read/write head 5024 isaligned to track along data blocks 5018, 5080, and 6002, as shown byarrow 5043, such that write element 5068 tracks along data blocks 5018,5080, and 6002 before read element 5052. This configuration allows forthe read-verification of data that is written by write head 5068. Inaddition, the “Y” shaped nanostructure forming the read element 5052 ispreferably pointed away from the direction of movement of read/writehead 5024 so that read head 5052 is not placed into a buckling conditionwith the rotation of disk 5016, 5076, or 6000.

FIG. 29 illustrates a side view of a read/write head 5024 that includesa Helmholtz coil formed of a pair of coils 5068 and accompanyingmagnetic storage media 300/400. As discussed above, the magnetic fieldgenerated for writing to magnetic media is between a pair of magneticcoils 5068. Thus, magnetic media 300/400 is positioned between a pair ofread/write heads 5024, each of which support one coil 5068, therebyforming a Helmholtz coil. Note that in this Figure, a pair of read-heads5052 are shown positioned on either side of magnetic media 300/400 inorder to enhance the ability of read-head 5052 to detect the magneticpolarization of magnetic nanoparticles 103/104 in data layer 202 ofmedia 300/400. Write-head 5068 is configured write data on perpendicularmagnetic media. Write-head 5052 is configured to write data onlongitudinal media.

FIG. 30 illustrates a magnetic nanoparticle 103/104/113/114 ornon-magnetic particle 118 frictionally fit within a carbon nanotube101/111. In order to form magnetic media 300/400, it is desirable thatthe magnetic nanoparticles 103/104/113/114 forming the magnetic mediaremain stationary within carbon nanotubes 101/111. One method ofmaintaining nanoparticles 103/104/113/114 in a fixed position withrespect to carbon nanotubes 101/111 is to form a frictional fit betweennanoparticles 103/104/113/114 and carbon nanotube 101/111. A frictionalfit is formed when the diameter “d” of nanoparticles 103/104/113/114 isequal to or slightly exceeds the diameter “D” of carbon nanotube101/111. Nanotube assemblies 100 and 110 are formed by press fittingnanoparticles 103/104/113/114 within carbon nanotubes 101/111.

FIG. 31 illustrates a carbon nanotube 101 containing magneticnanoparticles 103/104 or 113/114 and non-magnetic nanoparticles 118. Asingle nanotube 101 may contain a single nanoparticle 103/104, ornumerous nanoparticles 103/104. Non-magnetic nanoparticles 118 mayseparate individual magnetic nanoparticles 103/104 from abutting eachother. Non-magnetic nanoparticles 118 may also separate chains ofmultiple magnetic nanoparticles 103/104 that abut each other from othermagnetic nanoparticles 103/104. Separating individual nanoparticles103/104 or chains of nanoparticles 103/104 with non-magneticnanoparticles 118 functions to isolate and maintain the integrity of themagnetic polarizations of magnetic nanoparticles 103/104. In addition,it enhances the ability of a read/write head 5024 to locate and detectthe polarization of a single nanoparticle 103/104 or chains ofnanoparticles 103/104 when there are non-magnetic particles 118separating the magnetic nanoparticles 103/104 from each other.

Two exemplary data encoding schemes for disk 5016, 5076, and 6000 arenow described. The first encoding method is simple: a first polarityindicates a first data bit and a second polarity indicates a second databit. Thus, SNNNSSSNNNSSSSN=011100011100001, where S indicates a SOUTHpolarization and N indicates a NORTH polarization. A second and morecomplicated scheme involves the transitions between the first and secondpolarity being a first data bit and no-transitions are counted aszeroes. This counting transitions between polarities as a 1 is becausethere is a “double difference” in polarity, relative to 0, in otherwords, you go from +300 Oe to −300 Oe with a NS transition, or −300 Oeto +300 Oe with a SN transition, and thus transitions are easier todetect. Thus, a pair of dislike polarities define a 1. Everything notinvolved in a transition is counted as a zero. Thus,SNNNSSSNNNSSSSN=1010101001. This second encoding method is thereforeconsidered to be more robust than the first encoding method.

FIG. 32 depicts exemplary array of nanotube assemblies forming arotational marker 5022, a servo sector 5020, a data header 5034 and adata block 5018, as shown in FIGS. 19A and 19C. In general, FIG. 32illustrates a series of long rectangular boxes 100. Each of these longrectangular boxes is a carbon nanotube assembly 100. The carbon nanotubeassemblies 100 forming rotational marker 5022 and servo sector 5020 aregenerally perpendicular to the carbon nanotube assemblies 100 formingdata header 5034 and data sector 5018. However, this orientation ismerely exemplary. The carbon nanotube assemblies 100 forming rotationalmarker 5022 and servo sector 5020 may be positioned in a gently curvingarc relative to the carbon nanotube assemblies 100 forming data header5034 and data sector 5018. The direction of tracking of read/write head5024 over rotational marker 5022, a servo sector 5020, a data header5034, and a data block 5018 is shown by the blackened arrow 5043.

Rotational marker 5022 is depicted as being formed of carbon nanotubeassemblies 100 that are continuously filled with permanently magnetizedmagnetic nanoparticles 103 or 104, as illustrated by the long blackrectangles 100. The depiction of three parallel carbon nanotubeassemblies 100 forming rotational marker 5022 is merely exemplary.Rotational marker 5022 may be formed of any number of carbon nanotubeassemblies 100 that are continuously filled with permanently magnetizedmagnetic nanoparticles 103 or 104.

Servo sector 5020 includes grey code 5074 and fine positioninginformation 5076. Grey code 5074 is formed of a combination of carbonnanotube assemblies 100 that are continuously filled with permanentlymagnetized magnetic nanoparticles 103 or 104, as depicted by the longblack rectangles, interlaced with non-magnetic carbon nanotubeassemblies 100 that are either devoid of containing any nanoparticles103 or 104 or are filled with non-magnetic nanoparticles 118, asillustrated by the empty long rectangles that are filled with the colorwhite. The carbon nanotube assemblies forming grey code 5074 may includeany combination of carbon nanotube assemblies 100 that are continuouslyfilled with permanently magnetized magnetic nanoparticles 103 or 104 andnon-magnetic carbon nanotube assemblies 100. The carbon nanotubeassemblies 100 that are continuously filled with permanently magnetizedmagnetic nanoparticles 103 or 104 represent one of two digital magneticstates while the non-magnetic carbon nanotube assemblies 100 representsthe other one of two digital magnetic states. Note that the non-magneticcarbon nanotube assemblies 100 may include a hollow carbon nanotube 101that contains no nanoparticles 103, 104 or 118.

Fine positioning information 5076 is formed of carbon nanotubeassemblies 100 that include permanently magnetized magneticnanoparticles 103 or 104, depicted as being blackened boxes within longrectangles 100, and non-magnetic nanoparticles 118, depicted as beingwhite boxes interlaced with the black boxes within long rectangles 100.The permanently magnetized magnetic nanoparticles 103 or 104 in carbonnanotubes 5076A, 5076B, and 5076C form a patterned array that informs acontroller as to how to fine position the read/write head 5024 over datatrack 5019 to read data block 5018. The permanently magnetized magneticnanoparticles 103 or 104 contained in carbon nanotube assembly 5076Aindicate whether the read/write head 5024 is optimally positioned overdata tracks 5019A, 5019B, or 5019C or whether it is positioned too highwith respect to data tracks 5019A, 5019B, or 5019C. Carbon nanotubeassembly 5076B contains permanently magnetized magnetic nanoparticles103 or 104 that indicate whether read/write head 5024 is optimallypositioned over data track 5019. The permanently magnetized magneticnanoparticles 103 or 104 contained in carbon nanotube assembly 5076Aindicate whether the read/write head 5024 is optimally positioned overdata track 5019 or whether it is positioned too low with respect to datatracks 5019A, 5019B, or 5019C. If as read/write head 5024 tracks alongdirection 5043 over fine positioning information 5076 and detectsmagnetic nanoparticles 103 or 104 in carbon nanotube 5076A, but not incarbon nanotubes 5076B or 5076C, then the controller 5010 knows that theread/write head 5024 is positioned too high with respect to the datatrack 5019, 5019B, or 5019C and must reposition read/write head 5024. Ifread/write head 5024 detects magnetic nanoparticles 103 or 104 in carbonnanotube 5076C, but not in carbon nanotubes 5076B or 5076A, then thecontroller 5010 knows that the read/write head 5024 is positioned toolow with respect to the data tracks 5019, 5019B, or 5019C and mustreposition read/write head 5024. If read/write head 5024 detectsmagnetic nanoparticles 103 or 104 in carbon nanotubes 5076A, 5076B, and5076C, then the controller 5010 knows that the read/write head 5024 isoptimally positioned respect to the data tracks 5019A, 5019B, or 5019C.

FIG. 32 depicts three data tracks 5019A, 5019B and 5019C, which areshown for non-limiting exemplary purposes as being a single carbonnanotube assembly 100. Each data track 5019A, 5019B, and 5019C may bepositioned adjacent to a non-magnetic carbon nanotube 5086. Non-magneticcarbon nanotube 5086 may be formed of a single empty carbon nanotubethat contains no magnetic nanoparticles 103 or 104. Alternatively,non-magnetic carbon nanotube 5086 may be filed with non-magneticnanoparticles 118. Examples of non-magnetic nanoparticles includealumina, SiO₂, and dielectric materials. Each data block 5018 ispreceded by a data header 5034 that includes a header indicator 5078 andheader identification information 5082. Header indicator 5078 is shownin this example as being formed of alternating regions of permanentlymagnetized magnetic nanoparticles 103 or 104 interlaced withnon-magnetic nanoparticles 118. Header indicator 5078 may for example beformed of single magnetic nanoparticles 103 or 104 interlaced withsingle permanently magnetized non-magnetic nanoparticles 118. Headerindicator 5078 informs controller 5010 that it is about to encounterheader identification information 5082. Header identificationinformation 5082 is formed of rewritable magnetic nanoparticles 103 or104, as shown by the dashed lines. Header identification information5082 identifies the specific data block 5080. Data block 5080 is formedof rewritable magnetic nanoparticles 103 or 104. The rewritable magneticnanoparticles may have a lower coercivity than the permanentlymagnetized magnetic nanoparticles. Data block 5080 is then followed byerror correction code 5084, which is formed of magnetic nanoparticles103 or 104, which may be rewritable in a formatting process, orpermanently magnetized in a servo writing process.

FIG. 33 depicts a process flow diagram illustrating a method forfabricating magnetic media having magnetic nanoparticles 103/104 or113/114 contained within carbon nanotubes 101 or 111 encapsulated withina matrix 230 or 231. The process begins with START 7000. In step 7002,magnetic nanoparticles 103/104 or 113/114 and non-magnetic nanoparticles118 are fabricated. In step 7004, the magnetic nanoparticles 103/104 or113/114 are heated above their respective Curie temperatures todemagnetize them. Demagnetizing the magnetic nanoparticles 103/104 or113/114 prevents them from sticking together magnetically whileattempting to frictionally insert them into carbon nanotubes 101 or 111.In step 7006, the magnetic nanoparticles 103/104 or 113/114 are cooled.In step 7008, the magnetic nanoparticles 103/104 or 113/114 and/ornon-magnetic nanoparticles 118 are frictionally fit into carbonnanotubes 101 or 111 so that the nanoparticles remain in a staticposition with respect to carbon nanotubes 101 or 111 to form nanotubeassemblies 100 or 110. In step 7010, carbon nanotube assemblies 100 or110 are encapsulated in a matrix. The process ends in step 7012. Notethat this process is exemplary and non-limiting. For example, carbonnanotubes may be grown over the magnetic and non-magnetic nanoparticles.Note that this process is not required when magnetic nanoparticles103/104 are heated above their Curie temperature during fabrication step7002 and are not later exposed to magnetic fields which would cause theparticles to obtain a polarization prior to step 7008.

FIG. 34 illustrates a process flow diagram depicting a method of writinginformation to magnetic storage media that includes a carbon nanotube101 containing magnetic nanoparticles 103 or 104. The write processbegins with START in step 7100. In step 7102, read/write head 5024receives data to be written from controller 7102. In step 7104,read/write head 5024 locates the rotational marker 5022. In step 7106,servo information 5076 is read for fine-positioning of read/write head5024 preceding data block 5018 to center read/write head 5024 over thedesired data track 5019. In step 7108, servo information is used tocorrect the position of read/write head 5024 over data block 5018 asneeded. In step 7110, read/write head 5024 reads data header information5078 for coarse adjustment of read/write head 5024. If the data headerinformation 5078 does not match the desired data block that controller5010 wishes to position the read/write head 5024 over, then controller5010 directs read/write head 5024 to another location. The controllerthen reads the data header information to determine if the data block isGOOD or BAD. If it is BAD, the read/write head 5024 is directed bycontroller 5010 to skip to the next data block 5018. If it is GOOD,controller 5010 directs read/write head 5024 to write data onto datablock 5018 in step 7112. Then in step 7114, the controller 5010 performsa write-verify process by reading the written data with read/write head5024. In step 7116, the controller determines whether any errors weredetected. If errors were detected, in step 7118 a counter is reset andread/write head 5024 is directed to attempt to rewrite the data N times.If read/write head 5024 is unable to rewrite the data after N attempts,the data block 5018 is marked as BAD in the data header information 5082and the read/write head 5024 is directed to skip to the next data block5018. If no errors were detected, in step 7120 the controller 5010 isinformed that the write process was completed and which data blocks 5018were used. The write process ENDS in step 7122.

FIG. 35 illustrates a process flow diagram depicting a method of readinginformation from a magnetic storage media that includes a carbonnanotube 101 containing magnetic nanoparticles 103 or 104. The processbegins with START READ in step 7200. In step 7202, read/write head 5024and armature 5030 receives data block 5018 location information fromcontroller 5010. In step 7204, read/write head 5024 first locatesrotational marker 5022. Then in step 7206, read/write head 5024 readsservo information 5076 for fine-positioning preceding the data block5018 to center the read/write head 5024 over the data track 5019. Thenin step 7208, controller 5010 corrects the position of read/write head5024 over data block 5018 and data track 5019 as needed with servoinformation 5076. In step 7210, read/write head 5024 reads data blockheader 5034 for coarse positioning. If the data bock header 5034contains information showing that read/write head 5024 is located at thecorrect data block 5018, the read/write head remains in position. If thedata block header 5034 contains information showing that read/write head5024 is located at the incorrect data block, controller 5010 will directarmature 5030 to move position to a different data track 5019. In step7212, read/write head 5024 reads information from the data block 5018.In step 7214, the controller 5010 determines if there are anyread-verify errors with the error correction code. If there areread/verify errors, in step 7216 the controller will set a counter andreattempt to read the data N times. If the data cannot be read after Nattempts, the controller 5010 will direct the read/write head 5024 tomark the data sector as BAD in the data header information 5082. If noerrors were detected, the read data is sent to controller 5010 in step7218. The read process then ENDS in step 7220.

FIG. 36 illustrates a process flow diagram depicting a method of writingservo control information 5020, rotational marker information 5022 andheader identifiers 5078 to magnetic storage media. The process begins instep 7300. In step 7302, a strong bulk magnetic field is produced by alarge magnetic field source. The entire disk 5016 is exposed to thisbulk magnetic field. The bulk magnetic field magnetically polarizes allof the magnetic nanoparticles 103 or 104 forming the servo sectors 5020,the rotational marker 5022 and the header identifiers 5078. The magneticnanoparticles 103 or 104 forming the other parts of disk 5016 are thenrepolarized to a desired magnetic polarization during a disk format ordata writing process. The magnetic nanoparticles 103 or 104 forming theservo sectors 5020, the rotational marker 5022 and header identifier5078 are permanently magnetized in this process and are not alteredduring disk formatting or data writing processes. As discussed earlier,the magnetic nanoparticles forming servo sectors 5020, rotational marker5022 and header identifier 5078 may have a higher coercivity than theother structures of disk 5016 such as data blocks 5018. By having ahigher coercivity, data sectors 5020, rotational marker 5022 and headeridentifier 5078 cannot have their magnetic polarizations changed when aweaker magnetic field is used to magnetically polarize the magneticnanoparticles having a lower coercivity that form data blocks 5018. Notethat the permanently magnetized magnetic nanoparticles 103 or 104 formone digital state. The non-magnetic nanoparticles 118 or empty carbonnanotubes 101 which also form portions of servo sectors 5020 and headeridentifiers 5078 form the other digital state. In this manner a singlestep bulk magnetic field can write all of the servo control and markerand identifier information. In step 7304, a read check process isperformed to determine if the servo sectors 5020, marker 5022, andidentifier 5078 have been properly written. The process ENDS in step7306.

FIG. 37 illustrates a process flow diagram depicting a method for finepositioning of a read/write head 5024 over a data track 5019. The finepositioning process begins with START 7400. In step 7402, read/writehead 5024 reads carbon nanotubes 5076A, 5076B, and 5076C withinpositioning array 5076. In step 7404, if it is determined that nomagnetic nanoparticles 103 or 104 were detected, the controller goes tostep 7406 and repositions the read/write head 5024 over data track 5019with servo control information. If magnetic nanoparticles 103 or 104 aredetected in step 7404, then the controller 5010 determines if magneticnanoparticles 103 or 104 were detected in carbon nanotube 5076A and5076B but not in carbon nanotube 5076C in step 7408. If controller 5010determines that magnetic nanoparticles 103 or 104 were detected incarbon nanotube 5076A and 5076B, but not carbon nanotube 5076C, then instep 7410 the controller 5010 determines that the read/write head 5024is positioned to high with respect to data track 5019 and repositionsthe read/write head 5024 lower over data track 5019. In step 7412, ifcontroller 5010 determines that magnetic nanoparticles 103 or 104 weredetected in carbon nanotubes 5076C and 5076B, but not carbon nanotube5076A, the controller 5010 determines that the read/write head 5024 ispositioned too low with respect to data track 5019 and correspondinglymoves read/write head 5024 to a higher position over data track 5019. Ifcontroller 5010 determines that read/write head 5024 detected magneticnanoparticles 103 or 104 in both carbon nanotubes 5076A and 5076C aswell as 5076B, then the read/write head 5024 is correctly positionedover data track 5019. Then fine positioning process then ends in step7418.

While the technology has been shown and described with reference to aparticular embodiment thereof, it will be understood to those skilled inthe art, that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A magnetic storagemedia, comprising: a nanotubes; a first magnetic nanoparticle configuredto store binary information through magnetic polarization, said firstmagnetic nanoparticle contained within said nanotube; a second magneticnanoparticle configured to store binary information through magneticpolarization, said second magnetic nanoparticle contained within saidnanotube; and a non-magnetic nanoparticle, said non-magneticnanoparticle contained within said nanotube between said first andsecond magnetic nanoparticles.
 2. The magnetic storage media of claim 1,wherein said non-magnetic nanoparticle is comprised of a dielectricmaterial.
 3. The magnetic storage media of claim 1, wherein saidnanotube is encapsulated within a data layer.
 4. The magnetic storagemedia of claim 1, wherein said non-magnetic nanoparticle is comprised ofan insulating material.
 5. The magnetic storage media of claim 1,wherein said first and second magnetic nanoparticles and saidnon-magnetic nanoparticle are held in a stationary position within saidnanotube by friction.
 6. The magnetic storage media of claim 1, whereinsaid nanotube is a carbon nanotube.